Entering Thursday night's game in Sydney with just three wins all year and having conceded 178 points in four consecutive losses, the Bulldogs led until the 52nd minute, only to run out of steam with strike centre Monica Tagoai in the sin bin.
While they were far from their best, it was a 26th consecutive regular-season win for master coach John Strange's Roosters side, who remain on track to reclaim the title they lost to the Broncos last year.
The Roosters will now enjoy the bye afforded to the top two teams in week one of the six-team finals format.
Despite being huge underdogs, the visitors had the early ascendancy, and it took almost 12 minutes before Otesa Pule crossed for the Roosters to get the scoreboard ticking.
It didn't take long after that for Corban Baxter to slip a gem of a pass to Jessica Sergis, who ran 40m to score her competition-leading 15th try of the season.
Just when it looked like the floodgates would open, the Bulldogs worked their way back down the field and Tagoai powered her way over to bring her side within four points with 10 minutes left in the half.
Seven minutes later the Dogs' five-eighth Andie Robinson flew high over Baxter to pluck a pinpoint Tayla Preston bomb from the air and touch down.
With Preston's conversion, there were surprise 12-10 leaders at the break, leaving the shortest-priced favourites in NRLW history shellshocked.
To make matters worse for the Roosters, Baxter left the field on halftime for a head injury assessment and failed to return after the interval.
The Bulldogs stayed on top for the opening 13 minutes of the second stanza, before Tagoai was sin-binned by referee Karra-Lee Nolan for a hip-drop.
Five minutes later, Isabelle Kelly, starting in her 50th game as captain of the Roosters, tore through the middle of the Dogs defence and found prop Millie Elliott in support for the competition leaders to reclaim the lead.
Taina Naividi was next over the stripe and Canterbury's dream was over.
More tries followed to Pule, Mia Woods, Sergis and Jocelyn Kelleher for a final score that somewhat flattered the minor premiers.
Despite the loss, it was a brave effort from the Bulldogs and coach Brayden Wiliame in his final game at the helm before Mark O'Meley takes the reins in 2027.
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